Thread take-up for sewing machine



May 26, 1959 c. R. BACKLlN THREAD TAKE-UP FOR SEWING MACHINE 2 Sheets-Sheet 1 Filed April 15, 1958 QN 1 mm. M m v Y W mm \N m z \LN m i mwx MN mm 11 II QM, W Mr I a m mm m ww m fin WW m wkw ATTORNEY? May 26, 195 c. R. BACKLIN I 2,887,970

THREAD TAKE-UP FOR SEWING MACHINE Filed April 15, 1958 2 Sheets-Sheet 2 INVENTOR. 6' 14/ 6 6? R. Backlua ATTORNEY? n t ta s P n "I Application April 15, 1958, Serial No. 728,670

Claims. c1. in -24s This invention relates to. sewing machines and particularly to improved thread control means. in they form of'a rotary type take-up.

. It is an object of the present invention to provide a rotary type take-up which has substantially the same action inthe taking up of the thread during a stitch-forming cycle as is produced byfthe. usual link take-up, however, without the objectionable features of the link talke-up when operated at high speeds.

This is accomplished, according to' the present invention, by providing flexible members, and more specifically', endless'belts which are driven'intimed relation to the operation of the needle barduring the stitch-forming cycle so as to control the take-up of the thread-.' While one or more flexible members may be used in conjunction with each other to produce the required take-up cycle, it is at present'preferred to utilize-a sin'gle endless flexible band or belt provided with one or more take-up members or pins for engaging the thread as it passes between a pair of fixed guides on the'sewing machine.

A feature of the invention resides in the fact that the belt can be run at extremely high speeds and produce substantially the same take-up pattern as a link take-up without objectionable jars or shock encountered with the link take-up at the ends of its stroke.

Other features and advantages of the invention will be apparent from the specification and claims when'considered in connection with the drawings in which:

Figure 1 shows an end view, partly broken away, of the machine with the take-up in position thereon.

Fig. 2 is a sectional view taken along line 22 of Fig. 1.

Figs. 3-8 show diagrammatic views of the taike-up in various positions in the stitch-forming cycle.

While the take-up of the present invention may be lo cated in various positions on the sewing machine, such as on the arm facing the operator, it is herein illustrated as being mounted on the end face of the sewing head 10 which is carried at the end of the usual arm 11 supported above the base by the usual pedestal 12.

As shown in Fig. 1, a thread 13 being sewn passes from a supply (not shown) through the usual guides 14 to a tension device 15 and through a fixed guide 16 to the take-up means 17, then through a second spaced fixed guide 18 to a needle 19 carried by a needle bar 20 mounted on the head so as to be reciprocated through a stitch-forming cycle by a link 21 connected to an eccentric or crank 22 mounted on the needle bar drive shaft 23 driven from the main drive (not shown) for the machine. With this arrangement, the take-up means acts on the thread 13 as it passes between the two fixed guides 16, 18 so as to control the thread duringthe stitch-forming operation. The fixed guides 16 and 18 may be adjustably mounted on end plate 28 to alter the thread lead relationship to take-up belt pin 35 for more or less thread take-up action as required.

While several flexible belts or bands may be employed tam d May 2 5? for carrying f'a thread-engaging member through the required c'ycle, the invention is herein illustrated as having the take-up means formed by a single flexible belt 24 mounted to extend around a pair of pulleys or sprockets 25, 26 so as table driven in timed relation with the movement of. theineedle during'the stitch-forming cycle. Although'the belt may be made of articulated links, wires or bands of metal or the like, it is herein illustrated as comprising a continuous band 27 of rubber or plastic material which'may or ma'y not be provided with the usual wire orfabric ree'nforcement embedded therein.

In the herein illustratedform of the invention the sprocket '25 is the driving sprocket and the sprocket 26 is an'idler sprocket]- The driving sprocket is mounted in bearings 25 fixed on an: end plate 28 on the head and is connected to a gear 29 which meshes with a second gear 30'mounted on the end plate in line with the axis of the shaft,23 and driven from a crank pin 31 connected to the cran'k22 of the needle operating mechanism so thatthe gear 29 and sprocket'are rotated in predetermined timed relation to the operation of the needle during a stitchforming operation. Preferably, the connection of the gear 30 to the crank pin is'made through a resilient bushing 32 to facilitate the drive of the gear even though slight misalignment between' the crank pin and gear may be present. The idler sprocket 26 is mounted for free rotation by hearing 33 on the end plate 28 and supports the belt in extended position as shown.

The sprockets have teeth 25a, 26a projecting from the periphery thereofand the belt has formed on the inner face thereof a seriesofteeth 34 cooperating with the teeth on the sprockets to drive and control the movement of the belt. Because of the length of the belt in the illustrated form of the invention, the sprocket through its gearing' is rotated at twice the speed of the rotation of the needle'barshaft20' and the belt is provided with twice the number of teeth as the sprocket so that the belt will make a single 2 cycle of movement for each movement of the needle bar shaft. Of course, with belts of other lengths, the gear ratio" can be modified so as to produce a single complete movement of the belt for eachcycle of'the needle bar. I I

In order to control the thread during the take-up cycle, the belt, as shown in the drawings, is provided with at least one laterally projecting pin 35 which is adapted to engage the thread extending between the two guides 16, 18 and to form a take-up loop in the strand as required. Although the belt can be made of sucha thickness that the end .ofthe pin can be embedded therein, in the illustrated form of the invention an enlargement 36 is provided on the outer surface of the belt to receive and anchor one end of the pin to the belt. In order to obtain correct timing relationship of projecting pin 35 with needle bar movement, the driving sprocket is held on the shaft in bearings 25' by means of a set screw so that the driving sprocket can be set either fast or slow with movement of the needle bar.

While the other end of the pin could be supported by a second belt running synchronously with the belt 24, in the herein illustrated form' of the invention a cover plate 37 is provided in spaced relation to the head so as to overlie the take-up, and is provided with a guide groove 38 into which the end of the take-up pin projects. This cover plate will maintain the thread on the take-up pin during the slack movement of the thread.

If desired, a guide plate 39 can be mounted on the end plate 28 to overlie the-gears and to guide the thread into the space 40 in Which the take-up loop is located.

The. cycle of the operation of the take-up is shown in Figs. 3-8. As shown in Fig. 3, the pin 35 is starting to take up the slack in the usual threadloop which has been formed and passed about a bobbin (not shown). It continues to take up the slack in Fig. 4 and when it is in the position of Figs. 5 and 6 it is tightening the stitch in the fabric. As it leaves the position of Fig. 6, it will tend to give up thread from the take-up loop so as to form the loop to be passed about the bobbin during the next stitchforrning operation. This giving up of the thread from the take-up loop continues as the pin passes from the position of Fig. 6 through the positions of Figs. 7 and 8 and back to the position of Fig. 3 wherein the take-up of the thread in the loop passed over the bobbin starts and the cycle is repeated.

It will be noted that the thread will be accurately controlled by the take-up during the stitch-forming cycle and, furthermore, that at the time that the greatest tension is placed on the thread when the stitch is being tightened as shown in Figs. 5 and 6, the pin is fully supported by the sprocket wheel so as to exert an unyielding force in the tightening of the stitch.

The take-up of the present invention can be run at high speeds, in the neighborhood of needle speeds of 5,000- 6,000 stitches per minute, without undue shock to the machine since the motion is a rotary motion rather than a reciprocating motion.

Preferably, the belt is held relatively taut between the sprockets and provides a smooth uniform movement. While guides can be provided to engage the outer surface of the belt in the straight stretch of the belt extending between the sprockets or pulleys to prevent whipping of the unsupported belt at this point, it has been found that such guides may be omitted when a reenforced, relatively inextensible belt is used.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

I claim:

1. In a sewing machine having a thread take-up means disposed in predetermined relation to fixed spaced guide means and driven in timed relation with the movement of a sewing needle during a sewing cycle thereof, the improvement wherein said thread take-up means includes at least one elongate flexible member movable longitudinally and in a closed path and having thereon at least one thread engaging member to engage the thread disposed etween said fixed guide means.

2. In a sewing machine having a thread take-up means disposed in predetermined relation to fixed spaced guide means and driven in timed relation with the movement of a sewing needle during a sewing cycle thereof, the improvement wherein said take-up means comprises an endless flexible belt having at least one thread engaging member carried thereby to engage the thread disposed between said fixed guide means, and means to drive said belt through a complete cycle for each sewing cycle of the needle.

3. In a sewing machine having a thread take-up means disposed in predetermined relation to fixed spaced guide means and driven in timed relation with the movement of a sewing needle during a stitch-forming cycle thereof, the improvement wherein said take-up means includes a flexible belt movable in a predetermined closed path and having thereon at least one thread engaging member positioned to engage the thread disposed between said fixed guide means, and means for driving said belt to cause said member to move through one complete cycle for each stitch-forming cycle.

4. In a sewing machine having a thread take-up means disposed in predetermined relation to fixed spaced guide means and driven in timed relation with the movement of a sewing needle during a sewing cycle thereof, the im provement wherein said take-up means includes at least one driving sprocket and a second sprocket spaced therefrom, and a flexible member supported by said sprockets and havin means cooperating with said driving sprocket to move said flexible member in a closed path, said member having thereon at least one thread engaging member to engage the thread disposed between said fixed guide means.

5. In a sewing machine having a thread take-up means disposed in predetermined relation to fixed spaced guide means and driven in timed relation with the movement of a sewing needle during a sewing cycle thereof, the improvement wherein said thread take-up means includes at least one driving sprocket and an idler sprocket spaced therefrom, and a flexible belt supported by said sprockets and having means cooperating with said driving sprocket to move said belt thereby, said belt having thereon at least one thread engaging member, said member being in engagement with the thread disposed between said fixed guide means and being moved in a closed path for one complete cycle for each cycle of the sewing needle.

6. In a sewing machine having a thread take-up means disposed in predetermined relation to fixed spaced guide means and driven in timed relation with the movement of a sewing needle during a sewing cycle thereof, the improvement wherein said take-up means includes at least one driving sprocket having teeth on the periphery thereof and a rotatable idler spaced therefrom, and a flexible belt supported by said sprocket and idler and having teeth on the inner face thereof cooperating with the teeth on the driving sprocket to move said belt in a closed path, said belt having thereon a thread engaging member projecting from one side thereof to engage the thread disposed between said fixed guide means and to move said thread as required during said sewing cycle.

7. In a sewing machine having a thread tension device, thread take-up means disposed in predetermined relation to fixed spaced guide means and located between said tension device and a sewing needle and to be driven in timed relation with the movement of the sewing needle during a stitch-fo1ming cycle thereof, the improvement wherein said thread take-up means includes one driving sprocket and a second sprocket spaced therefrom, and an endless flexible belt supported by said sprockets and having means cooperating with said driving sprocket to drive said belt in timed relation to the movement of said needle, said belt carrying a thread engaging member in position to engage the thread disposed between said fixed guide means during movement of said member through a closed path to cause said thread to move through a predetermined take-up cycle during each stitchforming cycle.

8. A thread take-up means for a sewing machine adapted to be disposed in predetermined relation to fixed spaced guide means and driven in timed relation with the movement of a sewing needle during a stitch-forming cycle thereof comprising an endless flexible belt having at least one thread engaging member carried thereby in a predetermined path to engage the thread disposed between said fixed guide means, and means for driving said belt in predetermined timed relation to the stitchforming cycle.

9. A thread take-up means for a sewing machine adapted to be disposed in predetermined relation to fixed spaced guide means and driven in timed relation with the movement of a sewing needle during a stitch-forming cycle thereof comprising an endless flexible belt having at least one thread engaging member carried thereby, means including a drive sprocket for supporting and driving said belt to move said member in a predetermined path to engage the thread disposed between said fixed guide means, and means for driving said sprocket in predetermined timed relation to the stitch-forming cycle.

10. A thread take-up means for a sewing machine adapted to be disposed in predetermined relation to fixed spaced guide means and driven in timed relation with the movement of a sewing needle during a stitch-forming cycle thereof comprising an endless flexible belt having 6 at least one thread engaging member carried thereby, driving and idler sprocket means supporting said belt, relation to the stitch-forming cycle. said belt having means cooperating with the driving sprocket to drive the belt and move the member carried References Cited In the file 0f thls Pawnt thereby in a predetermined path to engage the thread 5- UNITED STATES PATENTS disposed between sa1d fixed gulde means, and means 2,358,493 Graesser Sept. 19, 1944 for driving said driving sprocket in predetermined timed 

